In a mixed-mail cancellation system, a vertical stack advance is used to move the mail into a nudger which nudges the mail away from the stack advance toward a mail separator. Mail is loaded upside down with the face toward the nudger. This allows cancellation of various sizes of mailpieces without having to shuttle the print head up and down. As the mailpieces are nudged away from the stack advance toward the separator, they are separated by a separation nip so that only one piece of mail at a time is allowed to be transported into the printing area for cancellation. In general, the mail separator includes a retard module and a feed module. The belt on the feed module moves the closest mailpiece downstream toward the printing area, while the belt on the retard module pushes the subsequent mailpieces upstream in order to singulate mailpieces from an incoming stack of mail. The retard module is placed against the feed module at an angle such that the feed belt and the retard belt form an inlet at the upstream end and a nip at the downstream end to ingest incoming mailpieces. The angle at the nip between the feed belt and retard belt is generally referred to as the ingestion angle. It has been found that, on the one hand, if the ingesting angle is too large, the mailpieces are more likely to be damaged at the nip. On the other hand, if the ingesting angle is too acute, it limits a thicker mailpiece to pass through the separator by geometry. In the past, a retard module with two sections has been used to meet these two contradicting requirements. As disclosed in U.S. Pat. No. 5,238,236 (Belec et al.), the retard module includes two sections, an upstream section and a downstream section, each having belts and pulleys for providing retarding forces. The two sections are pivotally connected to allow flexing motion therebetween. With this design, the downstream section which forms the separation nip can have a small ingestion angle to reduce the feeding damage while the upstream section forms a wider inlet with the feed belt. The urging structure enables the two sections to laterally flex about the coupling structure in response to the thickness of incoming mailpieces.
While the two-section design reduces the feeding damage and can accommodate thicker mailpieces, the design is somewhat complex. It is, therefore, desirable to provide a simpler and more cost-effective retard module that can meet the same requirements.